- Joined
- Mar 18, 2013
- Messages
- 200
- Reaction score
- 99
I'm in the process of checking out the systems in my aircraft ('79 Archer) and find that the glideslope doesn't give a flag (tried to fly an ILS). First thought is if the receiver is getting power. Without the engine running, I checked the power on the connector to the KN75 and was a little surprised at what I saw. Using a DVM it varies around 12.5VDC but it's not steady. Thinking there may be some noise on the line I pull out the scope and take a look. I find that between pins 1 (gnd) and 2 (+14) on the KN75 connector I see a square wave with a 50/50 duty cycle and alternating between 0 and 12VDC at a frequency of about 100Hz. The signal is clean and solid. Any ideas where something like this might be originating? From what I can tell this isn't correct as these pins should have a solid supply voltage. Am I mistaken or is something amiss and I'll have to get the shop involved to dig further?
Raymond Balister
Raymond Balister
